watkins



(No Model.)

F. O. WATKINS.

TELEPHONE. No. 369,376. I Patented Sept. 6, 1887.

wirtmooao gvwamcoz 6 mm, LMMW v 3 513 Bio (1 6 tom x e1 UNITED STATESPATENT FEECEO FRANK G. XVATKINS, OF PHILADELPHIA, PENNSYLVANIA,ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE UNITED STATES KROTOPHONE COMPANY,

OF NElV YORK, N. Y.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 369,376, datedSeptember 6, 1887.

Application filed November 15, 1886. Serial No 218,956. (No model.)

.To all whom, it may concern:

Be it known that I, FRANK (3. WVATKms, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented certain new and useful Improvements inKrotophones; and I do declare the following to be a full, clear, andexact description of theinvention, such as will enable others skilled inthe art to which it appertains to make and use the same, reference beingbad to the accompanying drawing, and to the letters and figures ofreference marked thereon, which forms a part of this specification 1 Myinvention has relation to certain new and useful improvements in theconstruction of krotophone receiving-instruments, and the object is toprovide a simple, reliable, and convenient form of receiver, whereby thevoice will be reproduced as received from the transmitter, thus avoidingall tendency to interruplion from foreign influences, such as inducedcurrents and other causes common to that class of receiving-instrumcntsusing a magnet or coil; and to these ends the novelty consists in thepeculiar construction and arrangement of the parts of the same, as willhereinafter be more fully described, and particularly pointed out in theclaim.

The figure in the drawing is a longitudinal section of my improvedlu'otophone-receiver.

The present invention is designed as an improvement in form upon thepatent granted July 6, 1886, to Edward S. Spaulding, No.

A is the receiver, and is provided with the usual ear-piece, B, which issecured to the receiver in any suitable manner.

0 is a diaphragm having an integral circu- 0 lar concave recess, a, inits center, and D is a second diaphragm, mounted a short distance infront of and parallel with the first one, 0,

being separated therefrom by a flexible washer, E.

The diaphragm G is preferably stamped up +5 from a piece of sheet-ironor other suitable conducting material, while the other diaphragm, D, ismade of any suitable non-con ducting but sonorous material, as amembrane or any of the woods. 5C

The inner face of the diaphragm D is provided with a small carbon wafer,d, corrc-' sponding to the size of the recess a, so that when theinstrument is held horizontal, as is its position while in use, thecontact ball 0 will by gravity complete the circuit between thediaphragm G and the wafer (Z. Of course, when the instrument is held orplaced at rest in a vertical position, the carbon ball 6 falls into therecess in diaphragm O, and breaks the contact. The wafer d is inelectrical connection with binding-post a and thediaphragm G, connectedto the post 1). Through the medium of the flexible washer E the twodiaphraguis may be adjusted with reference to 6 each other by tighteningor loosening the earpiece 13.

I do not broadly claim a contact between a diaphragm and a back support.

For a complete description of the operation of the instrument, referencemay be had to the patent to Spaulding, krotophone, granted July 6, 1886,No. 345,084,.

Having thus described my invention, what I claim is- The combination,with the diaphragm 0, provided with recess 0, of the wafer d and carbonball a, as set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

FRANK (3. WATKINS.

\Vitnesses:

THOMAS Cameron, Enw. KIDD.

